THERMOREGULATORY RESPONSES OF THE NORTH-AMERICAN PORCUPINE (ERETHIZON-DORSATUM BRUNERI) TO DECREASING AMBIENT-TEMPERATURE AND INCREASING WIND-SPEED

Average resting metabolic rate of five adult male porcupines (Erethizo n dorsatum bruneri) 0.23 ml O-2/g . h +/- 0.007 SEM, between 10 degree s C (T-k) and 25 degrees C, which is 70% of the value predicted by bod y mass. A T-b of 37.1 degrees C +/- 0.1 SEM was maintained between -10 degrees C and 25 degrees C, Calculated thermal conductance (between 6 degrees C and - 10 degrees C) was 87% of the predicted value. There w as no significant change in mean metabolic rate as a function of wind (up 4.3 m/s) at ambient temperatures (1 degrees C and -5 degrees C) be low their T-k. Under these same ambient conditions, with and without w ind, the skin surface and subcutaneous areas of the porcupine's rosett e region exhibited marked temperature lability. (C) 1997 Elsevier Scie nce Inc.